Arboretum Creek is a stream in Seattle, Washington, USA, whose entire length of approximately 4000 feet lies within the boundaries of the Washington Park Arboretum. Its average channel width is 4 feet and its average channel depth is 2 feet.

The creek's source is now the koi pond in Washington Park's Japanese Garden, near the playfield at the park's southern end. It also receives runoff from Rhododendron Glen and the Woodland Garden, as well as sub-surface drainage from the neighboring course of the Broadmoor Golf Club. It empties into Lake Washington via Willow Bay, itself a minor arm of Union Bay, having passed through numerous culverts under Lake Washington Boulevard.